The basic process of flash evaporation is described in U.S. Pat. No. 4,954,371 herein incorporated by reference. This basic process may also be referred to as polymer multi-layer (PML) flash evaporation. Briefly, a polymerizable and/or cross linkable material is supplied at a temperature below a decomposition temperature and polymerization temperature of the material. The material is atomized to droplets having a droplet size ranging from about 1 to about 50 microns. The droplets are then vaporized, under vacuum by contact with a heated surface above the boiling point of the material, but below the temperature which would cause pyrolysis. The vapor is cryocondensed then polymerized or cross linked as a very thin polymer layer.
Many electronic devices, however, require polymer composite layers for devices including but not limited to molecularly doped polymers (MDP), light emitting polymers (LEP), and light emitting electrochemical cells (LEC). Presently these devices are made by spin coating or physical vapor deposition (PVD). Physical vapor deposition may be either evaporation or sputtering. Spin coating, surface area coverage is limited and scaling up to large surface areas requires multiple parallel units rather than a larger single unit. Moreover, physical vapor deposition processes are susceptible to pin holes.
Therefore, there is a need for an apparatus and high deposition rate method for making composite polymer layers that may be scaled up to cover larger surface areas with a single unit and that is less susceptible to pin holes.